1,2-diaminocyclohexane and chemical process

ABSTRACT

Disclosed is a process for the preparation of 1,2-cycloaliphatic diamines from 1,2-aromatic diamines. In one embodiment, the process provides a method for making 1,2-diaminocyclohexane by the reaction of 1,2-phenylenediamine contained in a polar, protic solvent with hydrogen in the presence of a supported rhodium catalyst, ammonia, and a trialkylamine, and having enhanced overall conversion and selectivity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the filing date of U.S.Provisional Application No. 61/115,577 filed on Nov. 18, 2008, theentire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The disclosure herein relates to a process of chemical transformationemploying the steps of hydrogenation of 1,2-phenylenediamine(o-phenylenediamine; OPD) to the corresponding cycloaliphatic compound,1,2-diaminocyclohexane (DCH), by hydrogenating the aromatic diamine inwater containing ammonia and a trialkylamine in the presence of asupported rhodium catalyst.

BACKGROUND OF THE INVENTION

Litvin and co-workers (lzvestiya Akademii Nauk SSSR, SeriyaKhimicheskaya, 4, pp. 854-857, April, 1973) hydrogenated 1,3- and1,4-phenylenediamine in various solvents at 120° C., 1175 psia, in thepresence of supported Ru and Rh catalysts.

U.S. Pat. No. 4,181,680 relates to a process for hydrogenation of anaromatic bis-methylamine at 50° to 150° C., 500 to 2000 psig, in waterand the presence of a supported ruthenium catalyst and in the absence ofadded ammonia.

U.S. Pat. No. 5,360,934 relates to a catalytic hydrogenation process forconversion of aromatic amines to ring hydrogenated compounds in whichthe catalyst is rhodium on a kappa alumina support.

U.S. Pat. No. 5,981,801 relates to a method for preparation ofcycloaliphatic diamines by hydrogenation of the aromatic diamine in thepresence of an air or oxygen pre-treated ruthenium catalyst.

JP Patent No. 59216852, 5/23/83, Nippon Kayaku Co., Ltd. relates to ahydrogenation process for production of aliphatic diamines from thecorresponding aromatic diamines by use of a supported rhodium catalystin water and in the presence of sodium or potassium phosphate andammonia, a secondary alkylamine, or a tertiary alkylamine.

It would be desirable to provide an improved method for the synthesis of1,2-diaminocyclohexane that operates at low to moderate pressures toprovide commercially useful yield and conversion.

SUMMARY OF THE INVENTION

The invention provides a process for making 1,2-cycloaliphatic diaminescomprising contacting a 1,2-aromatic diamine with hydrogen in polar,protic solvent in the presence of a tertiary alkylamine, ammonia and aheterogeneous catalyst comprising at least one selected from the groupconsisting of Ru, Rh, Pd and Pt.

In one embodiment, the polar, protic solvents may have the structure ROHwhere R is hydrogen or an alkyl group. The alkyl group may have from 1to 6 carbons.

Suitable tertiary alkylamines include trialkylamines where the alkylgroup has from 1 to 20 carbon atoms. Examples include triethylamine,tripropylamine and tributylamine. In one embodiment, the trialkylamineis triethylamine.

In an embodiment, the heterogeneous catalyst comprises at least oneselected from the group consisting of Ru and Rh.

In another embodiment, the sum of the weights of Ru, Rh, Pd and Ptcomprises from 1 to 10 weight percent of said heterogeneous catalyst,for example, from 3 to 5 weight percent of said heterogeneous catalyst.Suitable catalyst supports include supports known to those skilled inthe art of heterogeneous catalysis to be substantially inert to aminesolvents. Examples include carbon, alumina and titania. Microporousmaterials that are substantially inert to amine solvents may also beused. Examples of such materials include zeolites and layered supports.

The heterogeneous catalyst may comprise an oxide of at least oneselected from the group consisting of Ru, Rh, Pd and Pt. In thisembodiment, the sum of the weights of Ru, Rh, Pd and Pt may comprisemore than 50 weight percent of the heterogeneous catalyst, for example70 or more weight percent. In another embodiment, the heterogeneouscatalyst consists essentially of said oxide.

The process of the above embodiments further comprising contacting withhydrogen at a temperature from about 120° to about 200° C., and at apressure of from about 1000 to about 2500 psig.

In one embodiment, the invention includes a process for making1,2-diaminocyclohexane comprising contacting 1,2-phenylenediaminecontained in a polar, protic solvent with hydrogen in the presence of atertiary alkylamine, ammonia and a supported rhodium catalyst, whereinsaid polar, protic solvent is selected from the group consisting ofwater, methanol, ethanol, isopropanol, and mixtures thereof.

Embodiments of the invention include contacting the feed with hydrogenat temperatures from about 120° to about 200° C., and at a gaugepressure of from about 1000 to about 2500 pounds per square inch gauge(psig). [Pressures reported as pounds per square inch gauge (psig) arerelative to one atmosphere. 1 pound per square inch=6.895 kilopascal.One atmosphere is equivalent to 101.325 kilopascals, and one atmosphereis about 14.7 pounds per square inch absolute (psia) or about 0 poundsper square inch gauge (psig)].

In one embodiment, the process uses a supported rhodium catalyst. Otheruseful metal catalysts may include ruthenium. In one embodiment, therhodium catalyst is supported on carbon and contains from about 1 toabout 10 weight percent rhodium. Other useful catalyst supports mayinclude alumina.

In another embodiment, the supported rhodium catalyst may contain fromabout 3 to about 5 weight percent rhodium.

The disclosures here provide an enhancement to such a process where theoverall conversion and selectivity are improved and the processoperating pressures are reduced, providing more favorable overalleconomics.

DETAILED DESCRIPTION OF AN EMBODIMENT

The aromatic diamine starting material is 1,2-phenylenediamine(o-phenylenediamine, OPD).

The hydrogenation process may be carried out in the liquid phase,typically in the presence of a solvent or mixture of solvents. Polar,protic solvents include water, alcohols (methanol, ethanol, isopropanol,etc.), and mixtures thereof. The convenience of using water as theprotic solvent for reasons of cost and ease in handling is advantageous.

The hydrogenation may be carried out primarily in stirred, batch, slurryoperations at temperatures from about 120° to about 200° C., and atpressures of from about 1000 to about 2500 psig.

Useful catalysts include rhodium supported on alumina, titania, zeolitesor carbon, generally containing from about 1 to about 10 weight percentrhodium, for example, from about 3 to about 5 weight percent rhodium. Inone embodiment, the support is carbon.

Useful zeolites include those zeolites that are known to those skilledin heterogeneous catalysis to be substantially inert in the presence ofamines under reaction conditions for converting 1,2-phenylenediamine to1,2-diaminocyclohexane. Such reaction conditions may include contactwith hydrogen, ammonia, 1,2-phenyldiamine and polar, protic solvents attemperatures from about 120° to about 200° C., and pressures from about1000 to about 2500 psig.

Natural or synthetic zeolites, a class of aluminum hydrosilicates (alsoknown as crystalline aluminosilicates), having an open structure ofthree-dimensional networks with defined pores and channels in thecrystal, may be used as heterogeneous acid catalysts in the process ofthe present invention. The particle size of the zeolite may be less thanabout 0.5 micron, for example less than about 0.1 micron, or less thanabout 0.05 micron. Examples of useful zeolites include faujasite(described in EP-A 492807), zeolite Y, zeolite Beta (described in U.S.Pat. No. 3,308,069), ZSM-5 (described in U.S. Pat. No. 3,702,886),MCM-22 (described in U.S. Pat. No. 4,954,325), MCM-36 (described in U.S.Pat. No. 5,250,277), MCM-49 (described in U.S. Pat. No. 5,236,575),MCM-56 (described in U.S. Pat. No. 5,362,697), PSH-3 (described in U.S.Pat. No. 4,439,409), SSZ-25 (described in U.S. Pat. No. 4,826,667) andthe like.

Other oxides may be useful as catalyst supports provided that they areinert in the presence of amines under reaction conditions as describedherein. For example, the preparation of sulfate-doped zirconium dioxideis disclosed in U.S. Pat. No. 5,149,862. Examples of suitable oxidicsupports may also include zirconium dioxide, titanium dioxide, hafniumoxide, yttrium oxide, iron (III) oxide, aluminum oxide, tin (IV) oxide,silicon dioxide, zinc oxide or mixture of these oxides.

In one embodiment, both ammonia (NH₃) and a tertiary alkylamine, forexample triethylamine, are added to the reaction mixture. The amounts ofthese constituents may be adjusted with a reasonable amount of trial anderror with the objectives of increasing conversion of starting materialand improving selectivity to DCH. Ammonia may be added at from about 3to about 15 molar equivalents relative to the startingo-phenylenediamine (OPD). The tertiary alkylamine, (for example:triethylamine) may be added at from about 0.002 to about 0.01 molarequivalents relative to the starting OPD.

The reaction mixture may then be worked up according to means known tothe skilled person with filtration to remove catalyst, followed bydistillation to isolate the refined DCH product.

EXAMPLE

Analysis of reaction products is done using gas chromatography (GC).Examples of suitable GC devices include, for example, the Agilent 6890 NGC (or current equivalent the Agilent 7890A GC system) available fromAgilent Technologies, Inc.; Life Sciences and Chemical Analysis Group;5301 Stevens Creek Boulevard; Santa Clara, Calif. 95051-7201 USA.

In an example, a mixture of 21.6 grams of OPD, 1.0 gram triethylamine,34 grams ammonia (NH₃), 3.3 grams ESCAT® 30 a 5 wt % Rh/CP 97 carbonpowder catalyst from BASF Catalysts, Iselin, N.J. (a global division ofBASF AG, Ludwigshafen, Germany) and 30 milliliters of deionized water isloaded into a 300 cubic centimeter volume autoclave, pressurized to 1000psig with hydrogen at room temperature and then heated for 2 hours at125° C. to a final pressure of 2000 psig. The reaction products areanalyzed by GC. These products are: 73.2 wt % 1,2-diaminocyclohexane(DCH), 9.2 wt % 2-aminocyclohexanol, 3.6 wt % OPD, 4.6 wt % phenazines,2.9 wt % cyclohexylamine and 3.9 wt % higher boiling materials.

In a comparative example, a mixture of 27.0 grams of OPD, 0.25 gramsodium methoxide, 2.7 grams of 5 wt % Ru/Al₂O₃ and 76 milliliters ofdioxane is loaded into a 300 cubic centimeter volume autoclave,pressurized to 800 psig with hydrogen at room temperature and thenheated for 4 hours at 150° C. to a final pressure of 1200 psig. Thereaction products are removed from the autoclave with dioxane aftercooling and analyzed by GC. The product is unreacted OPD, no conversionto diaminocyclohexane is observed.

The foregoing disclosure constitutes a description of specificembodiments illustrating how the invention may be used and applied. Suchembodiments are only exemplary. The invention in its broadest aspects isfurther defined in the claims which follow. These claims and terms usedtherein are to be taken as variants of the invention described. Theseclaims are not restricted to such variants but are to be read ascovering the full scope of the invention implicit within the disclosureherein.

1. A process for making 1,2-cycloaliphatic diamines comprisingcontacting a 1,2-aromatic diamine with hydrogen in polar, protic solventin the presence of a tertiary alkylamine, ammonia and a heterogeneouscatalyst comprising at least one selected selected from the groupconsisting of Ru, Rh, Pd and Pt.
 2. The process of claim 1 wherein saidpolar, protic solvent has the structure ROH where R is hydrogen or analkyl group.
 3. The process of claim 2 wherein said alkyl group has from1 to 6 carbons.
 4. The process of claim 1 wherein said tertiaryalkylamine has is a trialkylamine where the alkyl group has from 1 to 20carbon atoms.
 5. The process of claim 4 wherein said tertiary alkylamineis selected from the group consisting of triethylamine, tripropylamineand tributylamine.
 6. The process of claim 5 wherein said tertiaryalkylamine is triethylamine.
 7. The process of claim 1 wherein saidheterogeneous catalyst comprises at least one selected from the groupconsisting of Ru and Rh.
 8. The process of claim 1 wherein the sum ofthe weights of Ru, Rh, Pd and Pt comprises from 1 to 10 weight percentof said heterogeneous catalyst.
 9. The process of claim 8 wherein thesum of the weights of Ru, Rh, Pd and Pt comprises from 3 to 5 weightpercent of said heterogeneous catalyst.
 10. The process of claim 1wherein said heterogeneous catalyst comprises an oxide of at least oneselected from the group consisting of Ru, Rh, Pd and Pt.
 11. The processof claim 10 wherein said heterogeneous catalyst consists essentially ofsaid oxide.
 12. The process of claim 8 wherein said heterogeneouscatalyst comprises a support that is substantially inert to amines underreaction conditions for converting 1,2-aromatic diamines tocycloaliphatic diamines.
 13. The process of claim 8 wherein saidheterogeneous catalyst comprises at least one support selected from thegroup consisting of alumina, titania, zeolites and microporous layeredmaterials.
 14. The process of claim 1 further comprising contacting withhydrogen at a temperature from about 120° to about 200° C., and at apressure of from about 1000 to about 2500 psig.
 15. A process for making1,2-diaminocyclohexane comprising contacting 1,2-phenylenediaminecontained in a polar, protic solvent with hydrogen in the presence of atertiary alkylamine, ammonia and a supported rhodium catalyst, whereinsaid polar, protic solvent is selected from the group consisting ofwater, methanol, ethanol, isopropanol, and mixtures thereof.
 16. Theprocess of claim 15 further comprising contacting with hydrogen at atemperature from about 120° to about 200° C., and at a pressure of fromabout 1000 to about 2500 psig.
 17. The process of claim 15 wherein saidsupported rhodium catalyst comprises rhodium on carbon and wherein saidsupported rhodium catalyst contains from about 1 to about 10 weightpercent rhodium.
 18. The process of claim 15 wherein said supportedrhodium catalyst contains from about 3 to about 5 weight percentrhodium.